The Anatomy of Low Back Pain

Understanding the anatomy of the lumbar spine is key to understanding and managing low back pain.

The lumbar spine, commonly called the “low back”, consists of 5 vertebrae, and is located between the thoracic spine (which articulate with ribs) and the sacrum. The vertebrae themselves are given numbers by which they are identified, for example – Lumbar Vertebra 1 = L1, Lumbar Vertebra 2 = L2 and so on.

The normal lordotic curve of the low back is known as a secondary curve, and starts to develop in infancy due to weight bearing caused by learning to sit up and walk.  The low back is especially vulnerable to injury due to its weight bearing task and mobility.

Between each vertebrae throughout the whole spine (except for C1 and C2) is a intervertebral or fibrous disc. The purpose of the disc is to provide cushioning and shock absorption from weight bearing and movement. The intervertebral disc is comprised of the annulous fibrosis and the gel-like centre called the nucleus pulposus – these structures are work together to provide the shock absorption, and are both implicated in disc dysfunction and neurological symptoms.

Facet joints are the articulating surfaces of bone between vertebrae. These synovial joints are known as “plane” joints because their flat surfaces glide over each other. These joints may become inflamed due to injury to the joint or joint capsule itself, or due to compression of the intervertebral discs, forcing them to interact in a “close-packed” position. This close packed position means that the joint surfaces are forced closer together than normal, and will irritate the bone and cartilage during movement as they contact each other and create friction.

During an acute injury, the inflamed tissue in the joints may irritate the nerve roots as they exit the spinal cord via the intervertebral foramina. Eventually, if facet irritation is untreated, bony spurs may develop due to chronic inflammation and cause spinal stenosis – a decrease in the size of the “vertebral foramen” or spinal canal.

In the case of a “bulging” or herniated disc, pressure is exerted on the nerve root as it leaves the spinal cord via the intervertebral foramina. This pinching or pressure on the nerve root will cause sharp, shooting pain, especially when the patient leans forward (flexes) from the hip.  Symptoms will present in the areas that the compromised nerves supply.

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Massage Therapy and Anatomy – C1, C2 and Arthrology

Question of May 8, 2009 – The C1 and C2 vertebrae are considered “atypical”. Why is this, and explain how the 2 vertebrae relate to each other.

C1 and C2 are considered “atypical” cervical vertebrae because their form and function differ from the other 5 cervical vertebrae.

C1, also known as the ‘atlas’, is a circular ring of bone, which consists of anterior and posterior arches and 2 lateral masses. On the superior surface of the lateral masses are the superior articular facets, on which sit the occipital condyles. This allows for a “nodding Yes” motion of the head. On the posterior surface of the anterior arch is the facet for the odontoid process of C2. (see below).

There are no intervertebral discs between C1 and C2.

C2, also known as the ‘axis’, is somewhat similar to other cervical vertebrae, except for the presence of the “dens” or odontoid process – a bony protrusion which projects upward and articulates with the anterior arch of C1. (it is held in place here by the transverse ligament which attaches on both lateral masses of C1). The axis allows for rotation of the head, as in shaking your head “no”

How is this relevant in Massage Therapy? – This is a very vulnerable part of the body, so understanding the anatomical structures in the area is necessary in the case where a therapist may have clients with a WAD injury (whiplash associated disorder). Clients who may have had a bad slip, fall or accident (car or otherwise) in which acceleration/deceleration occured may have the potential for instability in this area. It is important, ergo, for the client’s physician to give a green light for massage therapy treatment, and then for the therapist to proceed carefully.

Question for today (easier today)

What does the term arthrology mean?

Massage Therapy and Anatomy – Cervical Vertebrae C1 & C2

Question of May 5th

Q: If the thoracic and sacral curves are considered primary, what spinal curves are considered secondary? What is a factor in the development of secondary spinal curves?

Answer: The cervical and lumbar lordotic curves are considered secondary. Weight bearing is the main factor in development of these curves – the cervical lordotic curve will develop first as a baby starts to move his or her head; the lumbar lordosis will develop when he or she learns to sit up and starts to bear weight.

Question of the Day
The C1 and C2 vertebrae are considered “atypical”. Why is this, and explain how the 2 vertebrae relate to each other.

Massage Anatomy review – Divisions of the spine, connection of Vertebrae

Question of April 15/09
How many divisions are there of the spine? (33 bones)
- There are 5 divisions of the spine: cervical, thoracic, lumbar, sacrum, coccyx
- Cervical spine has 7 vertebrae, thoracic 12, lumbar 5, sacrum 5, coccyx 3 – 5 (fused)

Today’s Question
How are the movable vertebrae of the spine connected (cervical, thoracic, lumbar)? In addition to movement, what other significant role do they play?